Firefighters battled a three-alarm fire that burned through the roof of a three-story apartment complex Tuesday evening in Orchards.

There were no reports of injury, and it is believed everyone escaped the building. The attic and roof of One Lake Place, at 5264 N.E. 121st Ave., became engulfed in flames around 8:09 p.m.

Neighbors shouted “get out of the building” as smoke billowed from the second floor. Initially dispatched as a two-alarm blaze, the call was upgraded 50 minutes later to a three-alarm fire.

The cause of the fire remains undetermined as of Tuesday night.

Captain Scott Willis, spokesman for Vancouver Fire Department, said investigators believe the fire started on the exterior of the building.

“It’s hard to say right now what started it,” Willis said. “But fire investigators are on scene.”

Firefighters were initially sent into the building at the north end of the complex and later commanded to evacuate. Crews from Vancouver Fire Department and Portland Fire & ­Rescue Department doused the blaze with ­elevated streams of water for nearly an hour to prevent the fire from spreading to nearby buildings. As the fire became contained, crews were sent back into the building.

Six units were involved initially and trees also caught on fire, according to emergency radio traffic monitored by The Columbian. Willis said that at full strength, 45 firefighters responded to the fire.

The “F” building, which caught fire, was evacuated along with adjacent buildings in the complex.

Residents clustered outside to watch while others in nearby buildings shut their doors and windows to keep out smoke.